Noncovalent Supramolecular Diblock Copolymers: Synthesis and Microphase Separation

Abstract

Supramolecular block copolymers ( PS-DAT- sb -PI-Thy ) were synthesized via noncovalent hydrogen bonding between well-defined thymine end-functionalized polyisoprene ( PI-Thy ) and diaminotriazine (DAT) end-functionalized polystyrene ( PS-DAT ). Three covalently linked block copolymers were also synthesized for comparison with the noncovalent supramolecular block copolymers. The complementary DAT/Thy interaction resulted in the microphase separation of the supramolecular block copolymer system. Detailed characterization of all functionalized homopolymers and block copolymers was carried out via proton nuclear magnetic resonance ( 1 H NMR) spectroscopy, gel permeation chromatography, matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and differential scanning calorimetry. The self-assembly process of supramolecular block copolymers was evidenced by transmission electron microscopy. Small-angle X-ray scattering was also performed to study the microphase separation of supramolecular and covalently linked block copolymers. Comparison of microphase separation images of supramolecular block copolymers and the corresponding covalently linked analogues reveals differences in d -spacing and microdomain shape.

Synthesis and Characterization of Asymmetric A1BA2 Supramolecular Triblock Copolymers via Noncovalent Interactions: A Solution and Solid-State Study

“…Furthermore, the end-functionality was modified to generate the triple H-bond-forming system, diaminotriazine (DAT)/thymine (Thy) for the respective triblock copolymers. As we described in our previous work, 42 the moderate association constant was observed for the DAT/ Thy system (κ a ∼ 900−1000 M −1 in solution) 39 and was strong enough to form supramolecular diblock copolymers. 2-Chloro-4,6-diamino-1,3,5-triazine (DAT-Cl) was reacted with amine chain-end-functionalized polystyrene via aromatic nucleophilic substitution to obtain DAT chain-end polystyrene S1 for all homopolymers and diblock copolymers.…”

“…Both low-magnification and high-magnification TEM images were obtained in order to search for and elucidate microphase separation as well as macrophase separation. One (PS 21K -b-PI 7K -OH) of the three covalently bonded PS-b-PI-OH diblocks was characterized previously 42 using SAXS and TEM. The microdomain structures from TEM and periodicities from SAXS are given along with those of the new PS 15K -b-PI 15K -OH and PS 15K -b-PI 45K -OH diblocks in Supporting Information, Figures S10−S13.…”

Synthesis and Thermal Analysis of Non-Covalent PS-b-SC-b-P2VP Triblock Terpolymers via Polylactide Stereocomplexation

“…Break seals were used for the introduction of reagents. Further details regarding the polymerization techniques are provided in previous reports [40][41][42].…”

Well-defined cyclic polymer synthesis via an efficient etherification-based bimolecular ring-closure strategy

“…More details concerning the techniques and the apparatus used are given in previous reports. [31][32][33] For example, the synthesis of the α-protected tert-butyldimethylsilyloxy-ω-functionalized with hydroxyl group PS (labeled as Pr-l-PS-4k) is described in detail. Styrene (5 g) was added to 80 mL of benzene, followed by the addition of TMEDA (2.50 mmol) and 1.25 mmol of the protected functional initiator 3-(t-butyldimethylsilyloxy)-1-propyllithium, and kept for 24 h at room temperature.…”